#!/usr/bin/python2

def judge_leap_year():
    year = float(raw_input('Enter a year: '))
    num1 = year % 4
    num2 = year % 100
    num3 = year % 400
    if (num1 == 0 and num2 != 0) or num3 == 0:
        print '%s is a leap year.' % year
    else:
        print '%s is not a leap year.' % year
if __name__ == '__main__':
    while True:
        judge_leap_year()
